RFC: new design of phosphor-time-manager on sdbusplus

[Deepak Kodihalli]

Hello Lei,


On 13/01/17 1:12 pm, Mine wrote:
> I’d like to discuss the design of |phosphor-time-manager| with the new
> sdbusplus interfaces.
>
> Please see below background and new design, let me know if you have any
> comments.
> Thanks!
>
>
>       Background
>
> Legacy time-manager expose below interfaces and methods:
>
>   * curr_time_mode
>   * curr_time_owner
>   * requested_time_mode
>   * requested_time_owner
>   * GetTime(target)
>   * SetTime(target, time)
>
> The implementation of |Get/SetTime()| will check the current time mode
> and owner, and do below:
>
>   * For |GetTime(<target>)|:
>       o If target is “bmc”, return BMC time;
>       o If target is “host”, return Host time;
>       o Else, return error
>   * For |SetTime(target, time)|:
>       o If target is “bmc”:
>           + If mode is NTP, return error
>           + If owner is “HOST”, return error
>           + Set BMC time
>       o If target is “host”:
>           + If owner is “BMC”, return error
>           + Set Host time
>           + If owner is “SPLIT”, save the diff between BMC time and Host
>             time;
>
>
>       New Design
>
> Now with sdbusplus, we have EpochTime interface, with |elapsed| property.
>
> After discussion with Li Yi and Vishwa, we decided to implement as below:
>
> Create two objects:
>
>   * |BmcEpoch|
>   * |HostEpoch|


Could these be just associations (via the association interface) to a 
single object? I'm not sure if the user the Epoch interface knows Host 
vs BMC? Shouldn't that be picked from the settings, or do we really have 
explicit calls to fetch/set bmc and host time?

> They both implements EpochTime interface.
>
> For |BmcEpoch|:
>
>   * When |elapsed()| is called, return BMC time;
>   * When |elapsed(us)| is called, use above SetTime(“bmc”) logic
>
> For |HostEpoch|:
>
>   * When |elapsed()| is called, return HOST time;
>   * When |elapsed(us)| is called, use above SetTime(“host”) logic.
>
> And there will be no “curr_time_mode/owner” or
> “requested_time_mode/owner” properties on DBUS.
>
> --
> BRs,
> Lei YU

Regards,
Deepak

>
>
>
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